PH and TA Concerns

[Quickbeam]

This is our first tub and we have really enjoyed it this summer. The tub is located at a summer cabin, and come the end of September it will be time for us to go home. We still plan on coming up to the cabin every couple of weeks during the winter, so we would like to keep the tub running during the time we are away, so we can use it when we get back, as I said every couple of weeks.
I don’t know what to do however, about the PH and TA. Out of the tap the PH is about 7.5, but of course this shoots up as soon as I aerate the tub. The problem is that I need to take my TA down very low before my PH stabilizes with aeration (when I say stabilize here, I really mean that the PH does not shoot up, as it really is not that stable). My PH will only stabilize (not shoot up with aeration) when my TA is down to 30. I will then add my 50 ppm borates, but the problem I’m having is that with my TA down at 30, even with the borates, if we don’t use the tub for a while, the PH starts to drift down. That’s not a problem when we’re here, as I can either run the jets or add a little bit of borax to boost the PH. The problem is if we are away for a couple of weeks at a time, I don’t know what to do about this???
Should I just dump the water and then not balance the refill, and have the PH at 7.5 initially, and then skyrocket when we use the tub, or should I keep the balanced water and risk having the PH drop down when we’re not here. I’m running some experiments right now, and over the last three days, with us not using the tub and no aeration in the tub, the PH has dropped from 7.9 to 7.4. I hate to see what it would drop to over 2 weeks. What I don’t know, and really don’t have any way to find out without dumping the water, is if we didn’t balance the water, how long it would take for the PH to drop back down to 7.5 after skyrocketing after aeration. I have just always balanced my water so I don’t have the answer to this.
Does anyone have any ideas on what we should about this? It almost looks to me like I need to decide between either high or low PH. If this is the case, I’m thinking it is probably better to have high PH??? This would mean dumping the water I have and then not balancing the refill. I'm not opposed to this if it is the right thing to do??? Again, any and all thoughts or suggestions would be appreciated.

[Quickbeam]

This is our first tub and we have really enjoyed it this summer. The tub is located at a summer cabin, and come the end of September it will be time for us to go home. We still plan on coming up to the cabin every couple of weeks during the winter, so we would like to keep the tub running during the time we are away, so we can use it when we get back, as I said every couple of weeks.
I don’t know what to do however, about the PH and TA. Out of the tap the PH is about 7.5, but of course this shoots up as soon as I aerate the tub. The problem is that I need to take my TA down very low before my PH stabilizes with aeration (when I say stabilize here, I really mean that the PH does not shoot up, as it really is not that stable). My PH will only stabilize (not shoot up with aeration) when my TA is down to 30. I will then add my 50 ppm borates, but the problem I’m having is that with my TA down at 30, even with the borates, if we don’t use the tub for a while, the PH starts to drift down. That’s not a problem when we’re here, as I can either run the jets or add a little bit of borax to boost the PH. The problem is if we are away for a couple of weeks at a time, I don’t know what to do about this???
Should I just dump the water and then not balance the refill, and have the PH at 7.5 initially, and then skyrocket when we use the tub, or should I keep the balanced water and risk having the PH drop down when we’re not here. I’m running some experiments right now, and over the last three days, with us not using the tub and no aeration in the tub, the PH has dropped from 7.9 to 7.4. I hate to see what it would drop to over 2 weeks. What I don’t know, and really don’t have any way to find out without dumping the water, is if we didn’t balance the water, how long it would take for the PH to drop back down to 7.5 after skyrocketing after aeration. I have just always balanced my water so I don’t have the answer to this.
Does anyone have any ideas on what we should about this? It almost looks to me like I need to decide between either high or low PH. If this is the case, I’m thinking it is probably better to have high PH??? This would mean dumping the water I have and then not balancing the refill. I'm not opposed to this if it is the right thing to do??? Again, any and all thoughts or suggestions would be appreciated.

Just after I posted this I thought there may be one other alternative. Maybe I should dump the water and just take the TA down to say 50. I'm thinking maybe with a TA of 50, and with 50 ppm borates, the PH will not drift down to a dangerous level, and even though it will still skyrocket after aeration, it might come back down to a reasonable level more quickly than if I left the water alone and did nothing to it. I also forgot to mention that the TA of my tap water seems to run somewhere between 150 and 170. Thanks again for any suggestions on this.

[jasonnau]

I've had my hot tub for 5 years and the only thing I've ever added is chlorine.  I change the water once every couple months and if something weird happens or it doesn't feel right I change it.   Just my opinion.    You might just be trying to hard.

[chem geek]

Why is the pH drifting down?  That implies you are adding something net acidic to the spa.  In particular, what are you doing to disinfect the spa when not in use?

[Quickbeam]

The only sanitizer I'm using is hydrogen peroxide. I have not seen it have any affect on my PH, either up or down, and I remember you had mentioned to me that hydrogen peroxide should not have an affect either way on my PH. I'm pretty sure in a previous post you had also mentioned that with a TA of 30 there was a danger my PH could trend down??? Did I misinterpret this? The only other thing in the spa is the "Clear Ray" system that Jacuzzi has, which I believe works as a UV sanitizer.
In any case, the PH is trending down, and I had thought it would be because I had such a low TA. Is this not the case?

[Quickbeam]

Chemgeek,
I should clarify that the PH only drifts down if we don't use the tub. If it sits idle for a few days then the PH starts to drift down. If we're using it, and running the jets, etc., the PH remains rock solid.

[chem geek]

Well, I'm not sure with the hydrogen peroxide why the pH is dropping, but at any rate you can have the TA higher to have the pH more stable in between soaks but of course then it will tend to rise more when there is aeration during the soak.  Other than using the 50 ppm borates for pH buffering (or using a phosphate buffer, but that produces a calcium phosphate mess) there's not much you can do except choose some sort of happy medium for the TA level.